Double-sided silicone coated liner

ABSTRACT

A double-sided silicone-coated liner, particularly adapted for use in self-wound tapes is described which is a paper upon which a silicone coating layer is deposited on one surface and a water vapor permeable silicone coating layer is applied on the liner&#39;s opposed second surface. The liner surfaces may optionally be clay coated, the clay coating adjacent to the water vapor permeable silicone coating layer also having water vapor permeability. 
     The tape made using this particular liner typically additionally has a carrier layer with an adhesive sandwiched between the silicone coating layer and the carrier. The tape is prepared by the steps of coating the liner with a silicone layer on a first side of the liner; drying the silicone layer; coating an adhesive onto an exposed surface of the silicone layer; laminating a carrier layer onto the adhesive; coating a second side of the liner, opposed from the first side with a water vapor permeable silicone layer; drying the water vapor permeable silicone layer; and remoisturizing the liner.

TECHNICAL FIELD

The invention described herein pertains generally to release linerswhich have been silicone-coated on both sides.

BACKGROUND OF THE INVENTION

The liner of pressure-sensitive products can be of different types,based on a film, a paper, or a combination of both. For self-woundtapes, the liner must be silicone coated on both sides.

Film liners can be silicone coated on both sides, and are stable withrespect to the ambient air humidity. However, they are expensive andconsequently of limited use. Only when the cost of the totalconstruction can justify the price differential between the subsequentlydescribed alternatives, can this solution be implemented commercially.Paper liners, generally a glassine (highly calendered) type of paper,can also be easily silicone coated on both sides, are relativelyinexpensive, but suffer regarding ambient air humidity characteristics.Composite liners, made out of paper and film, can easily be siliconecoated on both sides, but are either not stable to ambient air humidityor are expensive.

Alternative solutions can involve the use of a clay-coated kraft liner,which is widely used for single-side pressure sensitive labels, etc. Themain advantages of this type of liner is that it lies flat, possessesgood dimensional stability and obtains these properties at a reasonableprice. The clay coating provides a smooth surface with good hold out, animportant characteristic for applying a thermally or radiation curablesilicone coating, by any technique.

In order to use this type of liner for self-wound tapes, ittraditionally would have been clay-coated on both sides, to provideenough hold-out thereby allowing silicone coating on both sides withouta great deal of saturation of the paper. However, a problem which ariseswhen the same coating is applied to both the front and back sides ofthis type of liner, is that a "bursting" of the paper is likely to occurduring passage of the liner through the drying ovens. The "bursting" isinduced by the moisture contained in the paper which cannot come outduring the thermal drying/curing of the silicone coating as these claycoatings are relatively impervious to water vapor migration. Moreover,this characteristic does not allow proper remoisturization of the linerafter the drying/curing of the silicone, which is an essential step tokeep the targeted final product characteristics, particularly gooddimensional stability (i.e., the product will lay flat).

Standard one-side clay-coated kraft has also been tested in prior artsolutions, but requires a high silicone coating weight, sufficient tocompletely soak the liner with silicone. This mitigates against theeconomic attractiveness of the process. Additionally, such a heavysilicone coating weight makes it impossible to properly remoisturize theliner after drying/curing of the silicone.

Thus, as can be seen, prior art solutions to the problem have yet tosatisfactorily solve the technical issues facing the manufacture ofsmooth double silicone-coated liners, which are free from undesirabledefects on the surface.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a doublesilicon-coated liner which is adapted for self-wound tapes, whileshowing good dimensional stabilily when compared to former glassine-typeliners, and at an attractive cost to film liners.

It is another object of this invention to provide a liner with at leastone side relatively porous to water vapor migration.

It is still another object of this invention to provide a process forsilicone coating a paper on both sides, wherein the silicone coating issmooth, free from undesirable defects on the surface, allows foradequate remoisturization and is economic.

These and other objects of this invention will be evident when viewed inlight of the drawings, detailed description, and appended claims.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention may take physical form in certain parts and arrangementsof parts, a preferred embodiment of which will be described in detail inthe specification and illustrated in the accompanying drawings whichform a part hereof, and wherein:

FIG. 1 is a process schematic for making a double-sided self-wound tapewith carrier using a two pass process;

FIG. 2 is an expanded view in cross-sectional of an intermediate productproduced after the completion of the first pass in the process shown inFIG. 1;

FIG. 3 is an expanded view in cross-sectional of the double-sidedself-wound tape as realized after the completion of the second pass inthe process shown in FIG. 1;

FIG. 4 is an alternative construction of the double-sided product, knownas a free film;

FIG. 5 is a perspective view of the prior art illustrating burstinginduced by water contained in the liner paper when a non-water vaporpermeable coating is applied to both sides of the liner, and crackingdue to inadequate silicone coating;

FIG. 6 is a graph showing the dimensional stability of the doublesilicone-coated liner made by the process of FIG. 1 showing thedimensional stability of the product in relationship to the prior artglassine type liner;

FIG. 7 is an enlarged perspective view of the liner showing the "curl"effect induced by the shrinkage or elongation of the liner, due toambient air humidity variations, if the liner is not stable with respectto this physical parameter;

FIG. 8 is an enlarged perspective view of the liner showing "tunnels"when a prior art tape is applied to a flat board surface and exposed tohumidity variations;

FIG. 9 is an expanded view in cross-section of a product similar to thatshown in FIG. 2; and

FIG. 10 is an expanded view in cross-section of a product similar tothat shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings wherein the showings are for purposes ofillustrating the preferred embodiment of the invention only and not forpurposes of limiting the same, the Figures show a double sided linerwhich has been siliconized on both sides, yet which is not subject to"bursting" or "cracking".

FIG. 1 shows a process for making a double-sided self-wound tape. Whilethe tape is shown being prepared using a dual pass, there is no need tolimit the invention to such. The process can just as easily be practicedin one pass, in two passes, or in more than two passes, depending uponthe available equipment. In the first pass, base liner 2 is unwound frombase roll 24 and silicone coated with a first silicone formulation onone side 16 of base liner 2 at a first silicone coating station 26 toproduce a liner with a single-sided silicone coating 8. The siliconecoating is dried and/or cured in the drying and/or curing oven 28. Anadhesive layer 12 is then coated on top of silicone coating 8 at anadhesive coating station 30. The adhesive layer is dried and/or cured indrying and/or curing ovens 32, if necessary. If the adhesive used was ahot-melt adhesive, then the drying step is replaced with cooling.Likewise, if the adhesive is a radiation cured adhesive, then dryingwould be replaced by curing lamps. The product, which has a singlesilicone coating and an adhesive coating is remoisturized atremoisturizing station 34 through the non-silicone coated side of baseliner 2. Typically a carrier 4, unwound from carrier roll 36 islaminated on the adhesive 12 at laminating station 38. The tape is thenrewound at rewind station 40 to make a roll 41. The intermediate product10 of this first pass is shown in an expanded cross-sectional view inFIG. 2.

In a second pass, the tape 10 of the first pass is unwound from roll 41and silicone coated with a second silicone coating 6 on side 18, at asecond silicone coating station 42. It should be noted that side 18 isthe not yet silicone coated side of base liner 2. This silicone coating6 is dried and/or cured in drying and/or curing oven 44. A secondadhesive coating 14 is applied on top of carrier 4 at adhesive coatingstation 46 with resultant adhesive drying and/or curing in drying and/orcuring oven 48. Once again, if the adhesive used was a hot-meltadhesive, then the drying step is replaced with cooling. An appropriateamount of moisture is reapplied to the tape through the second siliconecoating 6 at a second remoisturization station 50 and the final tapeproduct 60 is rewound at rewind station 52. An expanded cross-sectionalview of this tape 60 is shown in FIG. 3.

In the above process, there is no requirement that either the first orthe second silicone layers be the same, and may in fact, be different inthickness and/or composition. Similarly, there is also no requirementthat either the first or second adhesive layers be the same, and may infact, be different in thickness and/or composition.

Base 2, in a preferred embodiment, will be a kraft paper. This paper canbe generally described as a paper made entirely from wood pulp producedby a modified sulfate pulping process. It is a comparatively coarsepaper particularly noted for its strength. It is usually manufactured ona fourdrinier machine with a regular machine-finished or machine-glazedsurface. It can be watermarked, striped, or calendered, and has anacceptable surface for printing. Kraft paper is most commonly made inbasis weights from 25 to 60 pounds (40-100 g/m²), but may be made inweights ranging from 18 to 200 pounds (30-300 g/m²).

In a most preferred embodiment, the kraft paper will be clay coated onboth sides, although the water vapor permeability characteristics of theclay coatings will be different. In general, clay is a natural, earthy,fine-grained material which develops plasticity when wetted but is hardwhen baked or fired. In papermaking, those clays containingpredominantly the clay mineral kaolinite are the most important and areused both as filler and as coating pigments. The paper may additionallybe calender finished, a term which is applied to any paper with asurface glazed by means of calenders or supercalenders.

While a kraft paper which is coated on both sides is typically used,there is no need to limit the invention to such. A single side claycoated paper could also be used to produce a stable liner. To providesufficient holdout for the silicone coating however, it would bedesirable to use a chemical coating (e.g., cellulosic, associative andpolymeric thickeners) on the non-clay coated side which allows passageof water to moisturize the paper. The coating must be capable of beingsilicone coated and typically ink-receptive.

In a most preferred embodiment, base 2 will be more open and lesscompacted than a supercalandered paper (glassine type), thereby showingless change in dimensions with change in moisture levels than with acomparable supercalandered paper. Good stability to changes in moisturelevels of a silicone-coated two-sided release liner is important. If thebase liner 2 shows changes in dimensions through the loss or gain ofmoisture, curl of the tape 60 will occur as shown in FIG. 7. This willresult in excessive scrap and production down-time at the customer site,where product will be unacceptable. Moreover, if the adhesive coating 14of the tape is laminated to a board, for example to fix large objectssuch as photographs, tunnels or wrinkles 70 as shown on FIG. 8, willdamage the appearance of adhesive layer 12, which will later damage thephotograph laminated onto it.

The paper used in the invention has far better dimensional stabilitythan prior art calendered paper, as seen in FIG. 6 showing theelongation/shrinkage relationship of both kinds of paper as a functionof the percent relative humidity. A sample of the paper was placedbetween two jaws in a controlled climate oven. One jaw was fixed on aframe and the other one was connected to an electronic extensiometerable to detect variations as low as 1 micron. The distance between thetwo jaws was initially set at 100 mm. The sample was then conditionedfor two hours at 90% relative humidity. After this conditioning period,the value read on the extensiometer corresponded to the zero point. Therelative moisture was then reduced step by step (every 10% relativehumidity) from 90% to 20%. At each step, a point was obtained which wasplotted in FIG. 6. This provided the desorption curve of the evaluatedsample. Correspondingly, measurements from 20% to 90% relative humidityprovided the data for the absorption curve for the paper.

The hysteresis shrinkage/elongation curve of the silicone coated paperof this invention using CHAM 623, commercially available from ChamTenero, Switzerland as the clay-coated kraft paper base, shown byreference numeral 56, is roughly half of that exhibited by one of thebest glassine liners, shown by reference numeral 54, known of the priorart. This figure indicates that the paper of this invention will changeless in dimensions when subject to changes in relative moisturehumidity. The significance of this resides in the fact that tapes ofthis sort are often stored in areas where the relative humidity can varyfrom 30 to 80% relative humidity. For the paper of the invention, thedimensional change in the paper between 30% and 80% relative humiditycorresponds to the positions marked as A₂ -A₁ =780-140=640 microns for100 mm evaluated. The corresponding prior art paper dimensional changesbetween the same relative humidity differences corresponds to thepositions marked as R₂ -R₁ =1440-280=1160 microns. The paper of theinstant invention will lie significantly flatter than that of the priorart.

The silicone formulations which are applicable to this type of inventionare quite varied in scope. Silicone, as used in this application refersto any organosilicon oxide polymer in which the structural unit is##STR1## where R₁ and R₂ are monovalent organic radicals. The physicalproperties of silicones depend on the size and type of the radical, theR/Si ratio, and the molecular configuration of the polymer (i.e. linear,cyclic, degree of crosslinking). These products are characterized byhigh thermal and chemical stability and unusual release from stickingand surface properties. The silicones can be solvent-based orsolventless, emulsion based or radiation cured.

One of the important facets of the invention is in the recognition ofthe interrelatedness of the liner barrier coating and silicone coatingwhich is applied to the printing or water vapor permeable side of theliner, i.e., side 18. Both the barrier coating and the silicone coatingmust function so as to permit the passage of water vapor both in and outof the liner.

As shown in FIGS. 9-10, for most applications, base 2 will be claycoated (3,5) on sides 16 and 18. The clay coating upon which siliconecoating layer 8 is applied upon, functions primarily to hold out thesilicone from the interior of the liner (i.e., to prevent saturation ofbase 2 with silicone). The clay coating 3 upon which the relativelywater vapor permeable silicone coating 6 is applied upon, functions topermit water vapor migration in several instances: (1) water vaporevaporation subsequent to the drying/curing of the first silicone layerin the first silicone drying oven 28; (2) water vapor reabsorption of atargeted amount of moisture at remoisturizing station 34; (3) watervapor evaporation subsequent to the drying/curing of the second siliconelayer in the second silicone drying oven 44; and (4) water vaporreabsorption of a targeted amount of moisture at remoisturizationstation 50.

The goal of this remoisturization is to bring the liner to a moisturelevel which closely approximates that found under ambient conditionswith 50% relative humidity. This will further minimize dimensionalvariations faced by the product during relative humidity swings from 80to 30%, as might occur at a customer's site. While the use of claycoatings are generally preferred due to the acceptance within theindustry, there is no need to limit the application to such. Othersealant coatings, other than clay are envisioned to be a part of theinvention which serve to perform the same or similar functions as thosepreviously described. A polyolefin coating would be one such example.

The silicone layer which is coated on side 16 of base liner 2 can be anytype of silicone. The second silicone formulation which is to be coatedon side 18, in general, and in a most preferred embodiment, will possesssufficient porosity to enable water vapor migration both in and out ofthe base. The water permeability can be measured by for example, theCOBB method (ISO norm 535-1991), in which a sample of paper is weighedjust before and immediately after the exposure of one side to waterduring a given amount of time. The increase in weight, expressed ingrams/square meter (g/m²) corresponds to the COBB index. As an example,a COBB 300, coated side, of 0.8 g/m² means that the coated side of theevaluated paper has been exposed to water for 300 seconds, and thedifference in weight (0.8 g/m²) is the quantity of water absorbed by thesample through the coated side.

From Table I, using a COBB 300 index, it can be seen that side 18 ismore porous in comparison to side 16, even after silicone coating.

                  TABLE I    ______________________________________    Base Paper            Silicone       Side 16    Side 18    ______________________________________    Cham 623            before silicone coating                           0.8 to 1 g/m.sup.2                                      11 to 13 g/m.sup.2            after silicone coating                           0.8 to 1 g/m.sup.2                                      2.5 to 3 g/m.sup.2    Glassine            before silicone coating                           34 to 36 g/m.sup.2                                      37 to 39 g/m.sup.2            after silicone coating                           10 to 12 g/m.sup.2                                      14 to 16 g/m.sup.2    ______________________________________

In a preferred embodiment, this water vapor permeable silicone isdiluted in an organic solvent prior to application, typically heptane,although other solvents are equally applicable and are well-known in theart, including combinations of solvents (e.g., heptane and toluene).

The choice of the appropriate silicone formulation is critical on thewater vapor permeable side of the liner, and also depends upon theadhesive selected for the construction. Inadequate silicone formulationwill show tight release, and cracking will be induced. As seen in FIG.5, cracking will result in cracks (˜1 mm long) 23 and bursts 22, whichcan be seen when unwinding the tape. These defects adversely influencethe properties of the product such as release, damage to the adhesivecoating, etc.

In general, adhesive layers (12,14) can be solvent-based adhesive (e.g.,acrylic or rubber), hot-melt adhesives (e.g., acrylic or rubber), oremulsion adhesives (e.g., acrylic/latex water dispersion) or radiationcured, all such adhesives being capable of flier radiation curing and/orcrosslinking, as is known in the industry.

The carrier can be a plastic or paper based. If the carrier is plastic,non-exhaustive exemplary types of suitable polymers would includepolyalkylene terephthalates (e.g., polyethylene terephthalate (PET),polyvinyl chloride (PVC), or polyolefins (e.g., polyethylene orpolypropylene)). The polymers may contain additives, and in general,usually do, such as antioxidants, fillers, colorants, and othercomponents which are known in the additive art. When the carrier ispaper based, non-exhaustive exemplary types of suitable compositionswould include tissue, which could be woven or non-woven.

When the carrier layer is polymeric based, equally within the scope ofthe invention is the concept of a laminated polymer, which contains manylayers, each serving specified purposes, which maximize the function ofthe product at minimal production cost.

EXAMPLES

The following non-limiting examples are illustrative of but a series ofexemplary combinations of components which are effective for use in thisinvention.

    ______________________________________    Example #1    Component          Quantity (lbs.)    ______________________________________    Formula 1:    Toluene            10    LF Naptha          63    GE SS-4330         12    GE SS-4335         2.5    GE SS-4300C        0.18    Formula 2:    Toluene            98    Dow Corning Syloff 7362.sup.a                       18    Dow Corning Syloff 7210                       2    Dow Corning Syloff 7367.sup.b                       0.2    Formula 3:    Heptane            76.6    Dow Corning Syloff 7146.sup.c                       20    Dow Corning Syloff 7048.sup.d                       0.15    Dow Corning Syloff 7210                       3.1    Formula 4:    Tolusol 5          81.7    Dow Corning Syloff 23                       14.7    Dow Corning C-4-2109.sup.e                       2    Dow Corning C-4-2117.sup.f                       0.6    Dow Corning 23A Catalyst                       1.3    Formula 5:    Heptane            70.0    Dow Corning Syloff 23                       16.7    Toluene            11.7    Dow Corning C-4-2117.sup.f                       0.6    Dow Corning 23A Catalyst                       1.3    Formula 6:    Tolusol 5          76.6    Dow Corning Syloff 7046                       20    Dow Corning Syloff 297.sup.g                       0.2    Dow Corning Syloff 7048.sup.d                       0.15    Formula 7:    Rhone-Poulenc PC-438.sup.h                       11.2    Toluene            59.6    Rhone-Poulenc PC-519.sup.i                       0.6    Rhone Poulenc PC-331.sup.j                       0.15    Formula 8:    Tolusol 5          76.6    Dow Corning Syloff 7046                       14    Dow Corning Syloff 7069                       2    Dow Corning Syloff 297.sup.g                       0.2    Dow Corning Syloff 7048.sup.d                       0.15    Formula 9:    Rhone-Poulenc 71822                       24.5    Rhone-Poulenc 71823                       3.5    Water              42    Formula 10:    Tolusol 20.sup.k   60    Rhone-Poulenc PC-438.sup.b                       7    Rhone-Poulenc PC-477.sup.l                       4.2    Rhone-Pouleac PC-519.sup.i                       0.75    Rhone-Poulenc PC-331.sup.j                       0.15    Formula 11:    Syloff 7610.sup.m  11.2    Syloff 7615.sup.n  20.8    Syloff 7611.sup.o  2.0    Formula 12:    Toluene            90    Dow Corning Syloff 7690.sup.p                       5    Dow Corning Syloff 7694.sup.q                       1    Dow Corning Syloff 7678.sup.r                       0.22    Dow Corning Syloff 7127.sup.s                       0.29    Formula 13:    Tolusol 20.sup.k   79    GE SS-4164A.sup.t  19.8    GE SS-4164B        0.2    GE SS-4163C        0.7    Formula 14:    Syloff 7044.sup.u  20    Syloff 7069        12    Dow Corning 7048.sup.d                       1.5    Formula 15:    GE SL-6000         12    GE SL-6010         11    GE SL-6020         0.73    GE SL-6030         9.6    GE SL-6040         0.16    Formula 16:    Heptane            73    GE SS-4330.sup.v   14.5    GE SS-4300C        0.15    Formula 17:    Toluene            59.6    Rhone-Poulenc PC-438.sup.h                       8.2    Rhone-Poulenc PC-290.sup.w                       1.0    Rhone-Poulenc PC-519.sup.i                       0.6    Rhone-Poulenc PC-331.sup.j                       0.15    Formula 18:    Tolusol 5          81.7    Wacker Dehesive 940A                       14.9    Wacker Dehesive V24                       1.3    Wacker Catalyst OL 0.05    Formula 19:    Heptane            79    GE SS-4191.sup.x   16.4    GE SS-4191B        0.3    GE SS-4192C.sup.y  0.4    GE SS-4259C.sup.z  0.4    ______________________________________     .sup.a silicone coating     .sup.b crosslinker mixture of 28% methylhydrogen siloxane and 71%     1ethynylcyclohexene     .sup.c silicone coating     .sup.d polymethylhydrogen siloxane     .sup.e trimethylated silica in xylene     .sup.f Fast Cure Additive tetra(22-methoxyethoxy)ethoxy)silane     .sup.g acetoxyvinylglycidoxypropylmethoxy silicone polymer     .sup.h polymethylhydrogensiloxane and polyorganosiloxanes     .sup.i polyorganosiloxanes in isopropyl alcohol with platinum catalyst     .sup.j polydimethyl(methylhydrogen)siloxane     .sup.k naphtha (petroleum), light aromatic and toluene     .sup.l polyorganosiloxanes and hydrogenated siloxane     .sup.m bis(methoxymethyl)ethyl maleate in silicone     .sup.n dimethylvinylated and trimethylated silica in silicone resin     solution     .sup.o methylhydrogen siloxane and dimethyl, methylhydrogen siloxane     .sup.p silicone     .sup.q bis(methoxymethyl)ethyl maleate in silicone     .sup.r dimethyl, methylhydrogen siloxane     .sup.s silicone catalyst in tetramethyldivinyldisiloxane     .sup.t dimethylpolysiloxane silanol in toluene and benzene     .sup.u pentamethylpentavinyl cyclopentasiloxane in silicone     .sup.v dimethylmethylvinylsiloxane     .sup.w 1ethynlcyclohexanol in polyorganosiloxanes     .sup.x dimethylpolysiloxane silanol and polymethylhydrogen siloxane in     toluene and bezene     .sup.y silicone catalyst (dibutyl tin diacetate) in toluene and benzene     .sup.z dimethylaminoethyoxypolysiloxane

    ______________________________________    Example #2    Component          Quantity (lbs.)    ______________________________________    Formula 20:    Toluene            10    LF Naptha          63    GE SS-4330         14.5    GE SS-4300C        0.15    Formula 21:    Toluene            98    Dow Corning Syloff 7362.sup.a                       20    Dow Corning Syloff 7367.sup.b                       0.15    Formula 22:    Tolusol 5          81.7    Dow Corning Syloff 23                       16.7    Dow Corning C-4-2117.sup.f                       2.0    Dow Corning 23A Catalyst.sup.aa                       1.3    Formula 23:    Rhone-Poulenc 71822                       24.5    Rhone-Poulenc 71823                       3.5    Water              42    Formula 24:    Heptane            70    Toluene            11.7    Dow Corning Syloff 23                       13.4    Dow Corning Syloff 291.sup.bb                       1    Dow Corning C-4-2117.sup.f                       0.6    Dow Corning XY-176.sup.dd                       0.6    Formula 25:    Heptane            76.6    Dow Corning Syloff 7146.sup.c                       20    Dow Corning Syloff 7048.sup.d                       0.15    Formula 26:    Dow Corning Syloff 7610.sup.m                       31.5    Dow Corning Syloff 7612.sup.cc                       3.5    Dow Corning Syloff 7611.sup.o                       1.4    Formula 27:    Tolusol 5          76.6    Dow Corning Syloff 7146.sup.c                       16.5    Dow Corning Syloff 7044.sup.u                       1.0    Dow Corning Syloff 7048.sup.d                       0.22    Formula 28:    Toluene            59.6    Rhone-Poulenc PC-438.sup.h                       8.2    Rhone-Poulenc PC-247.sup.ee                       1.0    Rhone-Poulenc PC-519.sup.i                       0.6    Rhone-Poulenc PC-331.sup.j                       0.15    Formula 29:    Tolusol 20         60    Rhone-Poulenc PC-400.sup.ff                       11.2    Rhone-Poulenc PC-519.sup.i                       0.6    Rhone-Poulenc PC-331.sup.j                       0.15    Formula 30:    Toluene            90    Dow Corning 7690.sup.p                       6    Dow Corning 7678.sup.r                       0.22    Dow Corning 7127.sup.s                       0.29    Formula 31:    Dow Corning Syloff 7044.sup.u                       32    Dow Corning Syloff 7048.sup.d                       1.3    Formula 32:    Tolusol 20         79    GE SS-4164A.sup.t  13.8    GE SS 4164B        0.35    GE SL-6000         2    GE SS-4163C        0.9    Formula 33:    Toluene            59.6    Rhone-Poulenc PC-438.sup.h                       10.0    Rhone-Poulenc PC-247                       1.5    Rhone-Poulenc PC-519.sup.i                       0.75    Rhone-Poulenc PC-331.sup.j                       0.20    Formula 34:    GE SL-6000         12.3    GE SL-6010         8.0    GE SL-6020         0.55    GE SL-6030         3.6    GE SL-6040         0.12    Formula 35:    Heptane            79    GE SS-4330         11.5    GE SL-6000         2    GE SL-6010         0.1    GE SS-4300.sup.v   0.18    Formula 36:    Tolusol 5          81.7    Wacker Dehesive 940A                       11.8    Wacker Dehesive 920                       1    Wacker Dehesive V24                       1.5    Wacker Catalyst OL 0.08    Formula 37:    Tolusol 5          76.6    Dow Corning Syloff 7146.sup.c                       16.5    Dow Corning Syloff 7044.sup.d                       1.0    Dow Corning Syolff 7048.sup.d                       0.22    Formula 38:    Heptane            79    GE SS-4191.sup.x   12.3    GE SS-4290         1.5    GE SS-4191B        0.4    GE SS-4192C.sup.y  0.5    GE SS-4259C.sup.z  0.4    ______________________________________     .sup.a silicone coating     .sup.b crosslinker mixture of 28% methylhydrogen siloxane and 71%     1ethynylcyclohexene     .sup.f Fast Cure Additive tetra(22-methoxyethoxy)ethoxy)silane     .sup.aa dibutyltin di2-ethylhexoate in xylene     .sup.bb methylhydrogen siloxane     .sup.dd dibutyltin diacetate     .sup.c silicone coating     .sup.d polymethylhydrogen siloxane     .sup.m bis(methoxymethyl)ethyl maleate in silicone     .sup.o methylhydrogen siloxane and dimethyl, methylhydrogen siloxane     .sup.cc bis(methoxymethylethyl)maleate in dimethylvinylated and     trimethylated silica     .sup.u pentamethylpentavinyl cyclopentasiloxane in silicone     .sup.h polymethylhydrogensiloxane and polyorganosiloxanes     .sup.i polyorganosiloxanes in isopropyl alcohol with platinum catalyst     .sup.j polydimethyl(methylhydrogen) siloxane     .sup.ee polyoganosiloxane     .sup.ff polymethylvinylsiloxanes in toluene     .sup.p silicone     .sup.r dimethyl, methylhydrogen siloxane     .sup.s silicone catalyst in tetramethyldivinyldisiloxane     .sup.t dimethylpolysiloxane silanol in toluene and benzene     .sup.v dimethylmethylvinylsiloxane     .sup.x dimethylpolysiloxane silanol and polymethylhydrogen siloxane in     toluene and benzene     .sup.y silicone catalyst (dibutyl tin diacetate) in toluene and benzene     .sup.z dimethylaminoethyoxypolysiloxane

Example #3

CHAM 623, a clay-coated Kraft paper, commercially available from ChamTenero, Switzerland, was silicone coated using a fast silicone solutionselected from Example #1. The added silicone layer was dried andresidual moisture contained in the liner migrated through the paperthrough the non-siliconized side during passage through thedrying/curing oven. Adhesive, such as Durotac-480, an acrylicsolvent-based adhesive commercially available from National Starch, wasapplied on this freshly siliconized side and dried. Afterremoisturization through the uncoated side, the liner was laminated ontoa 0.5 mil PET (polyethylene terephthalate) carrier at 1.5 g/100 in² (23g/m²).

A second silicone addition selected from the group consisting of Example#2 was applied, dried and cured in the ovens. An adhesive was applieddirectly on the polyester carrier and dried in the adhesive oven. Thedouble silicone-coated liner was remoisturized through the second watervapor permeable silicone layer at the end of the adhesive oven beforewinding.

While the product is shown with a carrier in FIG. 3, there is no need toinclude such in the product. As shown in FIG. 4, the tape 20 is shownwithout a carrier, and is known in the industry as a free film. The tapeis constructed similarly to that described previously in relationship toFIG. 3.

The invention has been described with reference to preferred andalternate embodiments. Obviously, modifications and alterations willoccur to others upon the reading and understanding of the specification.It is intended to include all such modifications and alterations insofaras they come within the scope of the appended claims or the equivalentsthereof.

What is claimed is:
 1. A product which comprises:(a) a base layer havinga first surface which is relatively impermeable to both water vapor andsilicone migration and a second opposed surface which is relativelyimpermeable to silicone migration, but permeable to water vapormigration; (b) a first sealant coating layer on the first surface of thebase layer which is relatively impermeable to a first silicone coating;(c) the first silicone coating layer on an exterior surface of the firstsealant coating; and (d) a water vapor permeable silicone coating layeron the second surface of the base layer.
 2. The product of claim 1 whichfurther comprises:(a) a carrier layer having a base-facing side and anopposed exterior side; (b) a first adhesive adjacent to the carrier onthe base-facing side and adjacent to the first silicone coating; and (c)a second adhesive adjacent to the carrier on the exterior side.
 3. Theproduct of claim 1 which further comprises a second water vaporpermeable sealant coating interposed between the second silicone coatinglayer and the second surface of the base layer.
 4. The product of claim3 wherein the first and second sealant coatings are selected from thegroup consisting of clay and polyolefin film.
 5. The product of claim 4wherein the first and second sealant coatings are clay.
 6. The productof claim 2 wherein the carrier layer is a polymer layer.
 7. The productof claim 1 wherein the polymer in the polymer layer is selected from thegroup consisting of polyalkylene terephthalates of alkylene number offrom C₁₋₄, polyvinyl chloride, polyolefins selected from the groupconsisting of polyethylene, polypropylene, polybutylene andpolyisobutylene and blends and laminates thereof.
 8. The product ofclaim 1 wherein the carder layer is paper-based.
 9. The product of claim1 wherein the adhesive is selected from the group consisting ofsolvent-based adhesives, hot-melt adhesives, emulsion adhesives andradiation cured adhesives.
 10. The product of claim 1 wherein the baselayer is a paper layer.
 11. The product of claim 1 wherein the paperlayer is a kraft paper layer.